340-yr winter temperature reconstruction, Chevalier Bay, Melville Island, Canadian High Arctic

Here, we present a well-calibrated quantitative temperature and snowfall record for the extended winter season (NDJFM) from Chevalier Bay (Melville Island, NWT, Canadian Arctic) back to CE 1670. The coastal embayment has a large catchment influenced by nival terrestrial processes, which leads to high sedimentation rates and annual sedimentary structures (varves). Using detailed microstratigraphic analysis supported by µ-XRF data, we separated the nival sedimentary units (spring snowmelt) from the rainfall units (summer) and identified subaqueous slumps. We used the thickness of the nival units to calibrate and predict winter temperature (r = 0.71, pc < 0.01, 5-yr filter) and snowfall (r = 0.65, pc < 0.01, 5-yr filter) for the western Canadian High back to CE 1670. Mechanisms: warm winters associated with increased winter snowfall and snow-water equivalent (SWE) are likely to lead to greater snowmelt runoff in spring, and ultimately to higher spring sedimentation rates (i.e. thicker nival units). This control of winter conditions over sediment transport through SWE in Chevalier Bay is in close agreement with studies on sediment process understanding from nival watersheds at Cape Bounty and the Boothia Peninsula. This interpretation is consistent along the three climate datasets considered for calibration (Mould Bay, Resolute Bay, and CRU TS).